DENVER, Colorado (CNN) -- Michelle Obama took center stage at the Democratic National Convention on Monday night, stressing her love for the nation and making her case for why her husband should be the next president.

Michelle Obama says Barack Obama embodies the "hope" to lead America as its next president.

"I come here as a wife who loves my husband and believes he will be an extraordinary president," she said of her husband, Sen. Barack Obama of Illinois, the presumptive Democratic nominee.

Michelle Obama -- who could be the nation's first African-American first lady -- pushed a theme of unity in light of controversial comments she made on the campaign trail that raised doubts about her patriotism.

"All of us are driven by a simple belief that the world as it is just won't do -- that we have an obligation to fight for the world as it should be," she said, closing the first night of the convention. Watch Sasha Obama review her mom's speech »

"That is the thread that connects our hearts. That is the thread that runs through my journey and Barack's journey and so many other improbable journeys that have brought us here tonight, where the current of history meets this new tide of hope.

"And you see, that is why I love this country," she said to a standing ovation.